The prior art contains a number of teachings relative to water injection in internal combustion engines, allegedly to improve the efficiency thereof. Some examples of the patented prior art are contained in U.S. Pat. Nos. 1,332,633; 2,879,753; 2,212,167 and 3,074,228. In general, such engines have not proven to be successful and have not been widely adopted commercially. The principal reason for this lack of success of water injected engines is their inability to operate at the high temperatures necessary to produce super-heated steam in the combustion chamber.
Customarily, the pistons of an internal combustion engine are sealed with piston rings and these rings require lubrication. The operational temperature of the engine is therefore limited to the highest temperature at which the lubricant can stand up, and such temperature is not sufficiently elevated to produce super-heated steam which the engine must produce to achieve the desired efficiency and to prevent water from entering the oil of the engine.
The present invention is believed to satisfy the key to providing a completely successful engine of the above class in which water is injected into the combustion chamber at desirable intervals to produce super-heated steam. This is accomplished in the invention by the provision of a unique ringless piston section formed of high temperature resistant material which may operate within a combustion chamber or cylinder of similar material with a relatively large clearance. This high temperature "displacement piston section" is backed up by a conventional ringed piston which operates in a relatively low temperature portion of the cylinder and which may be conventionally lubricated.
Additionally, the invention comprises means to charge the combustion cylinder or cylinders with air and to exhaust the combustion chamber at proper intervals. It includes means to inject fuel and water into the combustion chamber in accordance with a desired cycle of operation, an initial fuel igniter means and a heat sensing unit capable of detecting the temperature condition at which the engine can begin a fuel conserving alternate diesel steam cycle of operation.
Among the objectives realized by the invention are a more complete combustion of fuel by burning the fuel at higher temperatures than those attainable in known engines; the utilization of heat which is normally wasted to produce super-heated steam, and allowing this steam to expand on the power piston to obtain more power from the engine; to provide for cooling the engine by spraying water into the combustion chamber to control the temperature therein; and to provide control means to assure that water cannot be injected at temperatures below those necessary to produce super-heated steam.
The key element in achieving the first objective of more complete combustion under higher engine temperatures is the previously-mentioned ringless heat-resistant displacement piston which operates in the high temperature resistant power cylinder.
The air charging means for the engine may include a companion cylinder-piston unit adjacent each power cylinder with coordinated intake and exhaust valves, or the engine could be charged with a turbo-type supercharger.
With the former type of cylinder-piston engine charger, the engine will be built in multiples of the working and charging cylinder pairs, such as two, four, six or eight cylinders in the engine.
Other objects and advantages of the invention will become apparent during the course of the following description.